Effect of Probiotics on Blood Pressure : A Systematic Review and Meta-Analysis of Randomized, Controlled Trials

Background

Blood pressure (BP) can be controlled through diet and lifestyle modification. Not only are low-fat diets rich in fruits and vegetables and low in sodium suggested to lower BP [1-3], dietary constituents and supplements such as omega-3 fatty acids [4], garlic [5], and green tea [6,7] have also been found to improve BP control.
Probiotics have been studied for possible health benefits in improving immune system function [8] and preventing diarrhea [9,10]. These live microorganisms, when consumed in adequate amounts, may also improve BP through mechanisms including improving total cholesterol and LDL-c [11-13], reducing blood glucose levels and insulin resistance [14,15] and regulating the renin-angiotensin system [16,17].
Effects of probiotic consumption on BP have yielded inconclusive results. Therefore, a systematic review and meta-analysis of randomised controlled trials was conducted, on 9 eligible trials, with 543 participants. 7 studies reported a double-blind design, and one a single-blind design, and one did not report the blinding process. The probiotic source, species and dose used varied between studies, with total daily dose of probiotic consumption ranging from 109 colony-forming units (CFU) to 1012 CFU. Study duration varied from three weeks to nine weeks.

Main results

8 out of 9 studies reported a reduction in SBP after consuming probiotics, with a mean reduction ranging from 1.07 mmHg to 14.10 mmHg, of which 5 studies that reported a clinically significant reduction of SBP>5 mmHg.

The meta-analysis of 9 studies revealed a significant reduction of SBP by 3.56 mmHg (95%CI: -6.46 to -0.66, P<0.01) after probiotics consumption, as compared to the control group. Statistical heterogeneity was high among studies (I2=89%, P<0.05).

All 8 out of 9 studies that presented changes in DBP, reported a reduction after probiotics consumption (ranging from -0.9 to -8 mmHg), albeit only statistically significant in two studies.

The meta-analysis of 8 studies yielded a significant change of -2.38 mmHg (95%CI: -3.84 to -0.93, P<0.01) in mean difference of DBP as compared with control groups (I2=78%, P<0.05).

No meaningful relationship was found between the daily dose of probiotics consumed and reduction in SBP or DBP, although a subgroup analysis of studies with a daily dose of >1011 CFU showed a significant reduction in SBP and DBP, whereas studies with a daily dose of <1011CFU did not.

Conclusion

These results show that consumption of probiotics can significantly reduce SBP by 3.56 mmHg and DBP by 2.38 mmHg, which is similar to a recently reported effect of reducing salt intake by <2 g per day. This reduction is modest, but even a small reduction of BP may have relevant public health benefits and cardiovascular consequences. Therefore, probiotics may be used as a potential supplement to help prevent hypertension or improve BP control. Further studies may clarify the specific effects of different products, species and doses.